"Falsehood diffused significantly farther, faster, deeper and more broadly than the truth in all categories of information," the study found, "and the effects were more pronounced for false political news than for false news about terrorism, natural disasters, science, urban legends or financial information. We found that false news was more novel than true news, which suggests that people were more likely to share novel information."

The researchers defined fake news as "fabricated information that mimics news media content in form but not in organizational process or intent."

Fake news has, of course, been around in one form or another since the dawn of human history. But the internet has now given it unprecedented reach and power, with much of it driven on social media by bots. So how should we respond to this dispiriting real news about online fake news?

Google, Facebook, Twitter and other key internet players should ramp up their curatorial capacities, write 16 academic researchers in an essay for the same issue of Science.

"A new system of safeguards is needed," they wrote. They "urge the platforms to collaborate with independent academics on evaluating the scope of the fake news issue and the design and effectiveness of interventions."

Such a joint effort probably would prove valuable. But data scientist Soroush Vosoughi, who led the MIT study, acknowledged there will be no easy solution. "False information outperforms true information [on social media]," he stated simply. "And that is not just because of bots. It might have something to do with human nature."